A power washer pressure gun produces a powerful, high velocity stream of water which can be very dangerous if directed at a person. Thus, it is desirable to provide with such equipment safety features including rapid shut-off of flow to reduce the risk of injury to the operator and others. Additionally, when using conventional designs of power washer pressure guns, the operator is quickly fatigued. Operator fatigue is caused by the need to hold the trigger tightly against force at the trigger resulting from back pressure from the high pressure water acting on the flow valve. It is also caused by the need to hold the trigger tightly for an extended period of time, and by the need to overcome the tendency of the gun to twist and turn as a result of the strong recoil of the gun. The user must at all times accurately control the direction of the stream of water to avoid causing injury to others.
Handle systems having compound-action gripping mechanisms and quick release mechanisms are widely used in pliers, and in crimping and clamping tools.
U.S. Pat. No. 3,253,850 to Trusty, discloses a quick releasable carrying device having a handle 37, a toggle 19, and a pair of gripping jaws 13 and 15. The device permits easy handling of bulky objects, and provides means for easy release. Release is effected by flicking toggle release extension 51 with the index finger of the grasping hand. (col. 2, lines 39-42).
U.S. Pat. No. 4,353,240 to Undin et al. discloses a crimping tool with a four-pivot compound-action gripping mechanism and a pawl and ratchet mechanism, including a ratchet 24 and a pawl 34 mounted on handle 21. (col. 5, lines 35-47).
U.S. Pat. No. 4,381,661 to Wiener et al. discloses a crimping tool with a four-pivot compound-action gripping mechanism and a pawl and ratchet mechanism similar to that disclosed in U.S. Pat. No. 3,253,850.
U.S. Pat. No. 4,048,877 describes more fully the pawl and ratchet mechanism in U.S. Pat. Nos. 4,353,240 and 4,381,661. (col. 4, lines 30-44). U.S. Pat. No. 4,048,877 is hereby incorporated herein by reference.